French fries and potato chips are the biggest demons behind that pound-a-year weight creep that plagues many of us, a major diet study found. Bigger than soda, candy and ice cream. (AP Photo/Matt Rourke)

(Newser)
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Looking to lose weight? Skip the potatoes and concentrate on nuts and yogurt. That's the latest diet advice from a 20-year survey of 120,000 men and women on how the foods we eat affect our weight over the long term. “All foods are not equal, and just eating in moderation is not enough," the study leader tells the Washington Post.

The big villain in the survey was potatoes, particularly French fries—a serving of fries a day turned into an extra 3.35 pounds over a four-year period. Potato chips were not quite as bad, adding 1.69 pounds, and boiled potatoes just half a pound. Refined grains, like white bread, were also fattening, causing 0.39 pounds over each four-year period. Nuts, on the other hand, led to a half-pound reduction over four years, and yogurt kept off nearly a pound.